CGST procedural amendments revise input tax credit filing, gold dore bar credit reversal, advance ruling appointments, and registration forms. The amendment rules extend the time limit under rule 3(4), revise registration and input tax credit filing requirements, and introduce a special reversal mechanism for credit relating to additional customs duty on imported gold dore bar. They also update payment procedures for certain overseas digital service suppliers, prescribe the rank of officers for the Authority for Advance Ruling, and modify FORM GST REG-01, FORM GST REG-13 and FORM GST TRAN-1 to reflect revised registration and transitional compliance requirements.